One of the most effective methods of controlling fires of all kinds is directing a stream of suitable foam onto the fire. This foam is usually generated by mixing air with a liquid consisting of water into which has been introduced a material, such as a protein, that assists in bubble formation. The foam has a double effect: it not only cools the burning material below the flash point, but it also deprives it of oxygen. A third advantage of foam is that, because of the small amount of water involved, possible damage to the materials in the fire area is minimized. For these reasons, it is increasingly a common practice to incorporate permanently-installed foam generators in buildings in place of the conventional solid-water sprinklers. Generally speaking, such a foam generator would be installed in the upper part of a large building enclosure and directed downwardly toward the portion of the enclosure most likely to have a fire. However, foam generators require fairly large amounts of air and it is preferable that the air used be cool and free of inflammable gases generated by a fire. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide fire fighting apparatus for supplying fresh, cool air to a foam generator.
Another object of the present invention is the provision of apparatus combining a open vent and a foam generator in such a way that they begin their operations together.
A further object of the present invention is the provision of foam generating apparatus for association with a building, wherein fresh air is used instead of products of combusion.
It is another object of the instant invention to provide foam generating apparatus in which the air used in forming the foam does not contain hot combustible gases.
A still further object of the invention is the provision of venting apparatus for use with a foam generator, which apparatus can be operated either by a heat-fusible link or by the operation of the foam generator.
It is a further object of the invention to provide a fire fighting apparatus which is simple in construction, which can be readily manufactured from inexpensive materials, and which is capable of a long life of useful service with a minimum of maintenance.
It is a still further object of the present invention to provide fire fighting apparatus, including a venting door and a foam generator, in which the energy of fluid is not used only to operate the foam generator, but also to release the venting control apparatus are not necessary.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the spectification and covered by the claims appended hereto.